1. Field of the Invention
The present invention relates to a hydraulic compression tool of the type used for connecting electric wires or cables by compressing a connector or sleeve attached between and holding therein two wires, and more particularly to a compression head thereof having improved design.
2. Prior Art
Upon installation of electric wires or cables, a hydraulic compression tool is used for compressing a sleeve attached between and holding therein two cables. Such hydraulic compression tool has a compression head for pressing and deforming the sleeve. The sleeve of this type is generally tubular or C-shape in its cross section.
A conventional compression head is shown in FIG. 5. The compression head 50 comprises a generally Y-shaped stationary head 51, and a guide plate 52 reciprocally movable within the stationary head 51. Movable dies 53, 54 are slidably mounted on the guide plate 52.
The stationary head 51 is attached at its base portion 51a to an electrically or manually operated tool body (not shown) and the end portion 51b thereof is provided with a die 71. The head 51 is attached for limited rotational movement with respect to the non-shown tool body.
The guide plate 52 is attached to a piston 55 of the tool body (not shown) and when the tool is actuated by its motor pump or by swinging its manipulating handle, hydraulic fluid is flown into a cylinder 56, applying pressure on the piston within the cylinder 56 and hence the guide plate 52 attached thereto.
The guide plate 52 includes a stem or center support 57 extending from the center of the plate 52 and side supports 58, 59 extending at a predetermined angle at both sides of the center support 57. The center support 57 is provided at its top end with a die 72 and at its base portion with two screw holes 57a, 57b for receiving two guide pins 60 and 61, respectively. One end of each guide pin 60, 61 is screwed into the screw hole 57a, 57b and the other end is loosely inserted through a return spring 62, 63 into the movable die 53, 54.
Each movable die 53, 54 is provided at the inward surface 53a, 54a with a die 73, 74 and at the bottom surface 53b, 54b with a plurality of rollers 64, 65 so as to be sidable on the top surface 58a, 59a of the side support 58, 59. Provided at the end of each side support 58, 59 is a stopper 66, 67 preventing the rollers from coming off.
Upon installation, a sleeve 46 is set to rest in the central area of the compression head 50 surrounded by the aforesaid dies 71, 72, 73, 74 and then electric wires or cables 47 to be connected are inserted in the sleeve 46. When the piston 55 is moved forward, the four dies 71, 72, 73 and 74 press the sleeve 46, thus compressing and deforming the sleeve to connect the wires. The deformed sleeve 46 is shown in FIG. 6.
However, in the conventional compression head 50, the center support 57 is subjected to an undue load when the sleeve 46 is improperly set. This is shown in FIG. 7. Since the center support 57 is originally weak in its strength because of the two screw holes 57a, 57b for receiving the guide pins 60, 61, it is often broken by the applied pressure upon compressing.